The present technique disclosed herein generally relates to a variable ram of a blowout preventer, and more specifically, to a packer member used in such variable ram.
Wellbores in hydrocarbon reservoirs are formed by rotating a drill bit coupled to a drill string/drill pipe. Typically, a wellbore so formed includes a wellhead casing through which the drill bit and the drill string are inserted into the hydrocarbon reservoirs for extraction of hydrocarbons (fluid) from the hydrocarbon reservoirs. A blowout preventer (BOP) is usually mounted on top of the wellhead casing for regulating pressure of the wellbore. Further, the BOP often includes a variable ram to shut (close) the wellhead casing should pressure in the wellbore become uncontrollable.
Such a variable ram typically includes ram packer assemblies having elastomeric packers and metallic inserts, which may be configured to close on the drill strings inserted within the wellhead casing, to prevent blowout of fluid from the wellbore. At high pressure and high temperature conditions, the elastomeric packers at a bore face of such variable ram undergo significantly large deformation, which damages the bore face thereby resulting in leakage of the fluid from the wellhead casing.
Thus, there is a need for an improved variable ram that is configured to minimize or prevent leakage of fluid from the wellhead casing, and also minimize damage caused to an elastomeric packer in the variable ram.